From b336369c1e1ad88495895260a9068eb18bc48b6c Mon Sep 17 00:00:00 2001 From: Joshua Hoke Date: Mon, 25 Oct 2010 01:44:22 +0000 Subject: [PATCH] macb: Don't re-enable interrupts while in polling mode On a busy network, the macb driver could get stuck in the interrupt handler, quickly triggering the watchdog, due to a confluence of factors: 1. macb_poll re-enables interrupts unconditionally, even when it will be called again because it exhausted its rx budget 2. macb_interrupt only disables interrupts after scheduling macb_poll, but scheduling fails when macb_poll is already scheduled because it didn't call napi_complete 3. macb_interrupt loops until the interrupt status register is clear, which will never happen in this case if the driver doesn't disable the RX interrupt Since macb_interrupt runs in interrupt context, this effectively locks up the machine, triggering the hardware watchdog. This issue was readily reproducible on a flooded network with a modified 2.6.27.48 kernel. The same problem appears to still be in the 2.6.36-rc8 driver code, so I am submitting this patch against that version. I have not tested this version of the patch except to make sure the kernel compiles. Signed-off-by: Joshua Hoke Signed-off-by: David S. Miller --- Reading git-format-patch failed